UPDATE...not a VW question but I need some advice! Sorry aircooled guys!!!!

OK the thing is I've just come back from a quick blast .........(not telling, controlled test on a circuit)? in the Spyder, the first long fast drive @160+ for an extended period. And the fluid temp went thru the roof even at 110kph it climbed into the red. (EA82T mid mounted with radiator in the rear) see image below. The fan is mounted below the radiator and exits out the twin grills on the top of the rear deck. The radiator fan has no shroud so only blows up thru the diameter of the fan blades. Its seems to handle the temp generated at 60-80kmh but any higher than that it skyrockets. The current setup is picking up preheated air from the engine and turbo/exhaust before going thru the radiator. If you have a look at the shape of the car at the rear I'm thinking that there is turbulance at the grill area and this is counteracting the fan action? Any ideas, I'm thinking
1. Duct from below the engine thru the radiator? +
2. Remove top and bottom radiator tanks and clean?
3. Or maybe reverse the flow of air drawing in from the top grills and exiting below the engine?
I know its not aircooled but there are some very clued up people on this forum.
Thanks.

Below is not my car just an example.





[Edited on 7-12-2002 by speedster356]

[Edited on 26-1-2003 by speedster356]

[Edited on 26-1-2003 by speedster356]

Didn't the originals suck from the top and exit below, just like a volkswagen?

You may find that the aerodynamics of the car actually creates a lower-pressure area below the car than on top of the grilles, which would effectively create a natural flow from top-to-bottom even without the fans. Also, the air would be cooler, which would help.

I'm assuming that is an electric fan? Does it have a thermostat? Are you using Radiator Coolant in the radiator? Is the water clean? Is the thermostat working correctly or do you need to change it for one with a different operating temperature?

Is the pump working at its optimal speed? eg. speeding up the rotation of the pump can cause cavitation.

A better radiator may also help. Better quality radiators generally have more fins per inch for better heat dissipation, and more rows of tubes.

Also, what model Spyder is yours a replica of? If you get really desperate, you may have to resort to something like this: (See pic below)

PS. check out this link: http://takeoff.to/Spyder


[Edited on 7-12-2002 by KruizinKombi]

356
Is the radiator sealed to the bodywork ie with rubber strips when the panel is lowered, i think in my experience (13b extended prot in mazda truck) the best thing you can do is shroud the fan as the spill over the ends of the fan blades can be huge. Also is the radiator is crossflow, It made a huge difference when I recently put one in my truck.
Have you got the fan blades pointing the correct direction? , sorry about the silly questions but you never know
I am thinking of putting a turbo diesel in my 65 split bus and am going to run the airflow in at the bottom as yours and out through the vents as well, I can't see a problem with your system that a bit of fine tuning won't fix.
Cheers

Yes ur right kruzinkombi the originals did draw in from the grills! I have seen some drawings produced from Porsche R&D which shows a turbulant flow in the rear area above the grills due to the interupted flow over the windscreen. If there was uninterupted airflow (no windscreen)I would expect a high pressure area under the car due to the aerodynamic shape of the body? Much the same as an aircraft wing? Just guessing! Now that there is no Ovals Only Cruise on Sunday it looks like I'll be fiddling with the cooling system.

The fan is running 100% of the time.

I need to check if the thermostat is in there..the car was from cold old NZ.

I was using coolant but may not have been the right ratio......🙁I should know this as I work in the place that manufactures the stuff!!!

The water was not the cleanest when I looked in the overflow pot!

Standard waterpump ratio.

The radiator is not baffled to the underside of the engine lid.

Fan blade pitch....Hmmm need to check tomorrow.

Crossflow radiator....goes in at the top on one side and returns from the bottom on the other side...if so,yes?

I have read lots about burping the cooling system .....an air pocket in the coolant piping restricting flow. I guess this is a high spot in the system I am looking for?

I think I will try all these suggestions starting with the simple ones.

1.Check for thermostat and replace as required.
2.Clean system and recharge coolant at the right ratio.
3.Check pitch of fan for correct direction.
4.Fit baffles/shroud.
That should keep me out of the pub for a while......Mine is a 1955 550 Spyder replica, that drawing is a later RSK model.
Thanks guys I'll keep ya posted.

Pete,
If the motor doesnt have a thermostat, putting one in isnt going to make the engine run cooler. This isnt to say that you shouldnt put one in, as your motor would simply take a lot longer to reach normal operating (oil) temperature which is something Im sure you will agree, will protect the life of the motor. I was told from the guy that I bought my motor from (EA81T) that after a long hard drive, the turbo actually glows red! Thats @#$% hot! The reason partly for this is that these EA motors dont have intercoolers. This really compounds the under bonnet heat temps, not exculding the huge motor intake temps. Maybe fit that water to air I/C that we all talked about elsewhere on this forum. Id definately fit a shroud of some sort to segregate the actual motor compartment from the radiator compartment so the fan will only be blowing fresh air.
If all of that fails, you could sell me the car!? hee hee.....
Good luck, Im sure youll work it out....

Steve.

Yikes...red hot turbo + fibreglass! hehehe

Can you heat wrap the turbo and exhaust? Will it be of any use in reducing the under lid temps?

I'm not a water cooled expert but someone that is fairly cluey told me that you should not run without thermostat as this alows water to flow too quick - does not give it time to cool in rad..
Must admit that this advice reminds me of the "furthy" an engine needs a certain amount of exhaust back pressure - too little and you lose power...ummmm.
-
I would draw air in from top as well. As Larry told me " do you know how hot that bitumen gets on a hot day"

Yeah Glen I heard the same thing about thermostats. I know in an industrial application heat exchanger (reverse situation, heating with steam) that if you don't allow the steam to condense in the exchanger by using a steam trap (slowing flow) the efficiency is decreased hugely.
But then the industrial coolers we use we just have a flow control on the cooling water side, the more flow = more cooling effect?
Hmmmmm, buggered if I know!

Another question 4 ya.
Should I be able to see water flow if I remove the radiator cap with engine running?

[Edited on 7-12-2002 by speedster356]

No, You cant wrap the turbo and exhaust manifold as they loose their heat dissipating properties. You can try the "Red Turbo Test" yourself. At night, go for a good hard drive, pull over to the side of the road, lift the lid, and check out the turbo. Youll see that the thing actually has a deep glow! Sheilding the turbo and manifold from the motor would also help alot I think. Does it have its standard sheilds in place?

Turbo shielding
Just a side shield and where the exhaust bolts up. All else is exposed, not sure what the original had?

I tend to think that you should
1 - seal the border of the radiator to the underside of the engine lid around the perimeter of the louvres
2- shroud the fan edge to the underside of the radiator
3-reverse the airflow to pull from the top.
4- install a bleeder valve at the outlet of the radiator to remove air ( the header tank is above the rad isnt it?)

Oh the fan does have a small shroud around the tip...just checked. But the area that it pushes air thru the radiator is only the size of the fan. Most cars have a shroud from around the blade tips 2 the edge of the radiator? Hmmm did that sound right?

Yes you will need to seal right fom around the fan to the eouter edge of the rad
jeff

Don't have a lot to add, but I would be looking really hard at burbing the system. Most late model cars with xflow systems have air bleeder valves located at the high spots.
The other thought I had was is the fan rotating in the right direction? Seems like a really basic one I know. But if the radiators out of a fwd subie then the fan rotation would be for suck not blow.

Just for the record, in a watercooled motor without a thermostat, the water will flow too quickly and will not allow time for the heat in the engine to transfer to the water. The radiator won't seem too hot, but the heads will be cooking. A thermostat is a must!!

I agree with previous posts about sealing the radiator against the grills and drawing air down through it.

You're crazy not to wrap exhaust and turbo! I can grab hold of my (wrapped)turbos exhaust and not burn myself. Keeps a lot of heat away from the engine.
Might stop a nasty accident sometime too.

If you can possibly fit an intercooler then do so. It will lower the head temperatures dramatically.

Apart from engine temp problems, keeping heat IN the exaust and OUT of the intake will give you better performance.

Although this is starting to get off the subject heading, Ill try to explain the reasoning I dont think wrapping the turbo and dump pipe are beneficial. OK, turbo's under full boost/load operate at approx 1000deg give or take depending on all the variables you can think of. I think that keeping this heat inside the housing cant be good for a couple of reasons. The more heat that is placed on the turbine bearings and turbine itself, places more load on the cooling systems eg: oil and water which both flow through the turbo to keep it inside operating temps and to lubricate the (fluid) bearings. Wrapping the turbo housing will incubate this temperature and place even more load on the cooling system and turbo system itself, so you'd want to make sure that both of these liquids are changed regularly to keep them clean. Although the turbo exhaust housing isnt primarily the main cooling mechanism of the turbo setup, it still plays a roll of dispensing heat. I think this rising heat needs to have an easy path out of the engine bay by the way of heat sheilds. I know a couple of guys that have had to replace their actual turbos and manifold exhaust pipes (off turbo) when they have had them wrapped. I think this would be because of the immense temperature build up which then in turn causes immense pressure build up, which in turn causes too much expansion, which then cracks really imortant metals, which you dont want to crack. The next reason being, pressure inside the exhaust which is directly related to heat (+heat = +pressure) is an enemy of any engine. when the combusted gases leave a cylinder, they look for the easiest path, or lowest pressure route, to escape to atmosphere. The quicker the gasses escape, the more efficient a motor will run. You can see that by people fitting larger exhausts and match porting manifolds to heads. If the route (exhaust) that these combusted gases go through are considerably hot, remember the hotter the air, the higher the pressure, it causes a lot more resistance than these gases or mechanical parts would like. So, the motor would run less efficient and the mechanical parts that are putting up with the extra heat and pressures will break down before thier time. I know that some of the drag guys use thermo wrap a bit but I would presume this would be to keep the turbo and manifold from expanding too quickly and breaking things they dont want to break in 10 seconds.
This is just my opinion, so Im very interested to find out why people like you amazer, use it?. Could anyone tell me the pros of using this stuff?

Hutcho

Okay guys, about the turbo / turbo exhaust piping wrap. Please dont take this as me being a know - it - all, but as I work in the maintenance section of an oil refinery, believe it or not we see similar sorts of phenomenon in some of our very hot equipment (800°c +).

Using exhaust wrap or turbo jackets WILL keep your engine bay cooler. They will keep you engine bay cooler than running with a reflective shroud. However, because they insulate so well, all of the heat generated (apart from that which exits with the exhaust gases) stays in the exhaust housing / exhaust piping. When metals get too hot (actual temperature depends on the alloy) it undergoes a mechanism called High Temperature Oxidation, which appears like rust - the metal oxidises and the flakes off. The longer the metal is at these temperatures, the more it occurs, until you have a hole in your piping (a matter of years, but still)

Second. The overheating can place huge thermal stresses on turbo exhaust housings, causing them to crack.

Third, when you actually shut the engine off, it will take a helluva a lot longer for the turbo to cool down to a temperature where it wont form carbon deposits on the shaft / bearings. Ideally you would use a turbo timer that has a temp sensor on the turbo / oil system somewhere.

So, in my opinion (and thats all it is, I dont want to TELL people more experienced than I) turbo / exhaust wrap causes more problems than it cures, unless you run a drag car.

For the record, whether a car is intercooled or not wont have a significant difference on whether your turbo glows or not (even bog stock turbo cars will glow if you drive them hard enough).

Doug

Cool! some replies... Yep. I think that all a wrap is going to do, is reduce engine bay temps, which is good in a way for Peter but when his cooling system is working fine, it wont matter.
If you think of a tap (motor cylinder), that is running full pressure (exhaust gases) through a hose (exhaust) that is connected to it, you'll see that the water (spent gases) that comes out the end of the hose is pretty much equal (minus frictional losses) to the pressure thats coming out of the tap itself ie: the water runs freely. If you put another tap (the turbo) somewhere along the length of the hose and it automatically screwed down as temp rises, the pressure coming out the back of the hose will be less and the pressure between the two taps or cylinder and turbo, will be a much higher pressure potential, BUT as the second tap tightens down due to the rising heat, the water (exhaust gases) from the first tap (motor cylinder) flows to the second tap much less because of the resistance the 2nd tap or turbo has built up. When this happens, the weakest link will let go and this is usually the turbo because it is trying to hold back the pressure and heat.
I think with the wrap on the turbo, it would take a hell of a lot longer for the turbo bearings to cool down as Doug said. Where if your oil and water were in top nick, Id be surprised if you had to cool it down at all if you drove for a minute or two off boost. A perfect "turbo timer" would be as Doug said again, to place a thermocouple into the piping that runs from your turbo down to the sump. wire it through a relay so as your motor wouldnt turn off until the thermocouple senses the oil is at the right temp.
No, an intercooler wont have much effect whether the turbo glows or not, just retained heat and higher pressures.
An intercooler, especially a water/air will help reduce engine bay temps. The intake manifolds on the EA82's easily reach over 100deg which the manifold is soaking and giving off in the engine bay. Fitting an I/C would reduce that greatly. These are only my idea's as well. Ive had a coulpe of turbo'ed cars, but Im no expert at all! I too work in the maintenance field, and heat is one of our biggest enemies so we are always looking at ways to reduce it.
Please dont take me as a knowitall either. Its just that Im about to do a conversion along the same lines as Pete, so Ive been trying to find out as much as I can about this rear engined watercooled, turbo setup.
Id love some more comments!
Sorry about the lenth of my posts!
Hutcho

Your right sleepe3, water and carbon monoxide are different but the fundamental principals in the systems would be the same I think. Yeah, we should have been concentrating on the other issues I guess. Wouldnt the high intake temps be directly related to Thrermal Efficiency? Basically, I agree with everything youve said! In my first post I suggested an intercooler to reduce heat although I did say in one post that installing an I/C would reduce turbo temp but Doug pointed out that this would have no significant benefit and I conceed. I also fully agree that WRAPPING this stuff will reduce under bonnet temps but at what cost was all I was trying to point out. Hope I didnt peev anyone.:thumb:thumb:thumb
Cheers
Hutcho

So, Pete hows it going? Acheived positive results yet? Let us know!

Not had a chance to get into it yet. (I've had to do WORK at work!!!)
BUT: after a quick look.
1. Looks like I might have a high point on the return line from the radiator which might need to be bled.

2. But the fan is pitched correctly for the way it's rotating so that takes that one out.

This weekend I'll have time to give it a really good going over, looking at all that has been suggested here.
BTW, thanks for all the input guys I'm sure we can sort it out between us.

There is an excellent article on radiators in the latest Street Machine magazine. 🙂

Thanks kruizinkombi I'll check it out.

Well it looks like Most things have been covered..... I am a BIG Believer in Fan Shrouds... they can make all the difference... and covering of exhausts etc...with thermal wrap will STOP a lot of heat from the engine bay.. and I also believe that its better to have a thermostat than NOT having one.... As long as its the correct temp & pressure etc.... and the Radiator must be sealed against the engine cover... and I do believe the extra air vents will make a difference.... to reverse the Air fllow I believe You would need an air foil or scoop to force air into the Vents.... which I'm sure You don't want to do...
Best of Luck.... Make sure You have the correct Radiator cap..- whether it has a tank or not...... & the correct Coolant...
Best of Luck..... from My experience... I don't think You can see the coolant flowing with the cap off...... A FULL Fan Shroud is a must....:thumb

3. Has a thermostat, 82C. When I tested it just started to open at about the correct temp, but it was only open about 1mm if that. Should it be completely open at the stated temp or it it where it starts to open? Any ideas?
Have got a new one but not installed.

4. Did some temperature checks but only at idle and looks like I'm getting about only 12C temp change across the radiator, NOTE: this was at idle and car not moving.

[Edited on 14-12-2002 by speedster356]

OK heres what has been going on......looks like we've solved the cooling problems by:
1. Correct ratio of coolant to water.

2. Put 2 fans with a shroud.

3. Reversed the flow of air from pulling up under the car with all that engine heat to pulling thru the rear grills and out the bottom, still need to baffle from radiator to engine lid.

4. New thermostat.

Thanks for the input guys:kiss......but now....I put a temperature probe just after the turbo compresser and just before the throttle body inlet and gave it some, and on sustained boost the temperature got up to 100 deg C!!! That sounds pretty high to me, what do ya think? (no intercooler)

Boost is only about 7psi?
Heres a hint, dont take your new boost gauge out of the box and then drop it, it does nothing for the calibration!


[Edited on 26-1-2003 by speedster356]

I have heard all about this thermostat myth and have tested it out in person when I use to play with Turbos and my cruisers.

I had a 3B with the garret on it. I ran it without the thermostat and it ran hot.
I ran it with the thermo stat and it ran hot. I pulled the thermostat apart and put the outer only in, ie flowed as though it was fully open plus a little and it ran cool.

I agree you need an inline restriction to assist in lag time for the fluid to sit in the cores but to much of a good thing heads towards overload.

Now since yours is in a non standard setup with different cooling angles / flows / etc etc . I would suggest you have a play with the flow and how it effects cooling. You may find it quite suprising.

[Edited on 26-1-2003 by Buggy Boyz]

I have no idea what sort of inlet temperatures you should be expecting, but 100 degrees does sound pretty hot! Maybe the rice-burner boys may have some info on that kind if thing, being 'hi-tech' as they are. It can't hurt to ask. 🙂

Maybe it's time for an intercooler or some water injection to get the intake temps down?

Intercooler seems the way to go, and as you said the only problem would be ensuring that there is a sufficent airflow through the unit.
I'm swaying more to the air/water unit and a duct system from just in front of the engine at the bottom and exiting out the bottom rear of the engine. (full duct over the top of the engine where the intercooler is mounted). Most likely have to add a small fan to try to keep the heatsink problem at bay (build up of heat when not on boost and at idle etc).
I have started to shape the foam mould and will most likely build using carbon, never worked with carbon so it will be interesting?
The other mod will be to add even more natural airflow through the radiator (as opposed to forced with fans) to aid cooling at higher speeds, this will be much the same deal as the intercooler duct and will pick up on the other side of the crank centerline in front of the engine at the bottom of the car and tie into the radiator top (cool air).
The thing is with all these mods I'm adding weight........so all the carbon or glass ducting will have to be light!!!!
Hehehe, this is fun stuff......

[Edited on 28-1-2003 by speedster356]

Make sure you post some photos for us!:thumb

I have exhaust wrapped the pipes only. Not the housing. I have completely boxed in the housing and blow cool air through it and out underneath the car. I am more than happy to have my exhaust rust through. Its easy to replace. I can go to any muffler shop and buy a few bends. The alternative is not very smart. Have your engine overheat or not be able to drive it to its potential, or possibly even the speed limit.

Pressure in front of a turbo is great. Thats what makes it spin. Exiting a turbo is another matter yes. I think our exhausts would have less restriction than factory since they would have to have a heap more bends and length to travel from the front of a car and meet noise and emissions standards? If the theory is that the keeping the exhaust hot increases pressure then hopefully it would cancel out. We at least have to remember that there is never a perfect solution to any of our problems.

I'm going to assume that subarus didnt overheat. So why is this car? I assume cos the engine & radiator are at the back and not getting the airflow. So you have to compensate for that.

To keep the engine cool you have to keep the heads and pistons cool. Keep the intake temps down. There's a reason intercoolers were invented. The intake air cools the heads and valves. So colder air is better. You can throw more water at it, bigger radiator, but eliminate the source of the heat as much as you can beforehand. Of course you cant blow hot air through a radiator and expect it to cool. Wrap the exhaust and blow that heat out behind the car.

Try as best you can to eliminate the source of the heat first. I think it makes a lot of sense. Hoping I dont come accross as a butthead here. This is what I have done (see pic) The turbo shouldnt be there in front of the fan or even in the engine bay, but that is how I have inherited the project. I have plans of fixing that up as soon as santa brings me a good MIG welder. (cheap bastard he is! - no more socks n undies. I want a MIG!)

oops didnt know there was 2 pages to that thread.

Good post!:thumb

I see ya point Amazer, I've started to ring around today for an intercooler. I don't think an air/air is the way to go as cool air as at a premium at the moment but a nice remote mounted air/water with radiator should not be 2 hard to fit somewhere breezy.

Pete, good to see you getting some results. Dont know if it has been mentioned before, but what about trying to shroud/separate the radiator from underneath and bring two large ducts up into the shroud. It would then be totally segregated from the motor heat. You could still leave the fans in there as well.
Blue, I WISH I was taking the soob wagen but unfortunately, it isnt finished. Im using Valla as an excuse to have it finshed. Besides, funds can only LEAK out, not pour out otherwise there would be an in-house audit and I certainly dont want that!
Amazer, that shroud around you turbo.... THATS amazing! How does it go?? Keep it cool enough?
Pete, You REALLY need to put in an AIR/WATER intercooler. Im not too surprised from those intake temps your getting. In your first paragraph, you said you were thinking of using an air/water ic and then started talking about using duct to cool the intercooler down. Have I gotten this wrong? The water inside the ic system is what cools down the "heatsink". You can put the radiator that you use with the system anywhere you like to keep this water cool.

Yeah Hutcho I have my head up my arse when it comes to IC's, I'm learning as I go😀
I was going to duct if air/air, but now air/water is the best way to go for the very reason you mentioned.
Trying to get a cheap Liberty IC at the moment. The dissadvantage is all the stuff to drive it....pump etc, all adds weight. I will need an EJ20T after this.:o

hee heee... no worries, I just wasnt sure, Pete.
Dont know if Ive mentioned it before but I picked up a EJ20T ic and water pump for $200. from mrt.com.au I think it was. Theyre both in absolute excellent nick. All I need to get now, Is a motorbike radiator and the piping made up. Theyre pretty easy to come by I think as the WRX owners of these cars pretty much toss them in favour of air/air ic's. I dont think the whole setup wiould weigh THAT much, maybe 5kg's and with the extra performance and reliability you will get, Im sure youll forget all about that extra weight!!!

Hutcho wrote:Amazer, that shroud around you turbo.... THATS amazing! How does it go?? Keep it cool enough?

I've never ran it without the shroud, it would be pretty suicidal to do that. I'm running the heater boxes and a butchered set of extractors. The 4 pipes merge right in front of the engine fan so it would be sucking very hot air without it. What you cant see is the kombi heater fan on the right that is blowing hot air though the top of the shroud. I dont notice any engine temperature problems without the fan running but it does make the shroud touchable. I dont have a temp gauge at all. But without the water pump running the temps skyrocket and it doesnt like to run, wont idle. You can just see the subey intercooler on the right hand side in the dark.


[Edited on 29-1-2003 by amazer]

You can see the exhaust in this pic so you know why there's a shroud.

Sorry to come into this post so late.

You definitely need to bleed the air out of the cooling system. I put my bleed tank at the highest point. I have two radiator caps, one for filling, and one that bleeds to the siphon tank. Do you have a siphon tank. below is a pic of my bleed point / tank (not finished in that pic)



I think you definitely need to suck air through a radiator. If you try and blow through it, the air from the fan comes off the fan blades at an angle, a different angle to the radiator fins. This results in a lot of turbulence but not a lot of flow through the radiator. Drawing through create a low pressure which sucks the air through parrallel to the radiator fins.

The fan shrouds are absolutely positively essential. The fan creates a low pressure behind the radiator. Air will try to rush in to replace the low pressure. If you have no shroud, it just comes in from the sides of the fan. If you have a shroud, it has to come through the radiator.

Wrapping the exhaust and turbine housing reduces under bonnet temps and increases HP. If you want longevity don't wrap the turbine, just shield it, but wrap the exhaust. People think the exhaust turbine is driven by pressure, it isn't really. It is driven by the energy of the hot gas, kinetic energy. The hotter you keep the gas the more energy it has to drive the exhaust turbine. If you cool the exhaust gas you lose that energy and instead try to drive the turbine with pressure, back pressure from the pistons, not a good idea, not very efficient. High performance turbo cars try to keep the exhaust length to turbo as short as possible to keep in as much heat as possible.

100 deg C for a turbo non-intercooled is normal. An intercooler will cool the intake gas which has the advantaged of keeping the engine cooler (already discussed), but the main effect is to increase the density of the air. The higher the density, the higher the mass of air pumped into the engine, the higher the power made.

was that everything? I know most people covered those points, I just thought I would add my perspective

If you can find somewhere for a air-air intercooler go for one of those. A air to water IC will at best cool the air to water temperature. what's your water temp now, 100+degC? Unless you have a dedicated water system, which will be more added weight. And then the water temp has to be higher than the cooling air temp. And the intake air temp has to be higher than the water temp again.

A air to air IC at best will cool it to air temp, (a bit above, but much cooler than the air/water IC). I'm sure you will see air/air is used by anyone serious.

My brothers Silvia has a very small compact intercooler in front of the left hand front wheel. It would be small enough to jam in you car somewhere. Duct or blowing air from somewhere shouldn't be too much of a drama

[Edited on 29-1-2003 by Baja Wes]

you could also consider water/meth injection. I've help friends put together such systems. Whilst very primative they are effective. The other big factor in you're excessivly high intake temp could well be that the turbo is overspeeding and outside of its efficiancy island. This really gets the air nice and toasty 🙁 I'd call Ray Hall (turbo guru) and ask for his suggestions. Perhaps a hi-flowed T28 or so could deliver more air at less boost much cooler. And lastly somewhere in this large thread I noticed someone asking what temps were normal for the intake. Well the cooler the better really, the king of the turbos the R34 gtr with a huge Trust bar and fin front mount IC can take like 2bar /30psi (when modded of course) and the inlet charge is less than 10deg above ambiant temp!! thats awsome :bounce

Just for those that haven't figured it out, air gets hotter as it is compressed.

You can calculate what temperature it should get to when compressed. A good approximation is reversible adiabatic (means no heat is transferred to or from anything else) equation. All units need to be absolute.

T1/T2 = (p1/p2)^(y-1)/y

=> T2 = 303K / (14.7psi/21.7psi)^(1.4-1)/1.4

=> T2 = 339K which is 69 deg C

So just from compressing the air to 7 bar, the air temperature will increase from 30 deg C to 69 deg C. Then of course the turbo housing adds a bit more heat, and soon you up to 100 deg C.

Of course if it is sucking in warm air at 45 degC, then the outlet temp from the turbo will be 82 deg C.

That's basically what I said but in a less confusing way 😀

The other reason you need a fan shroud is so that it forces air through the entire radiator and not just teh bit in front of the fan. As teh fans are round the corners wouldn't see a lot of use without the shroud. Help increase the pressure of flow as well.

I've been through all the problems you are describing to some extent with my EJ20T powered speedster.

Fit your radiator in the front, this is the only way to get decent air flow at speed without putting large ugly ducting on your car which I'm sure you don't want.

Fit the Legacy air/water chargecooler and the extra radiator up front ahead of the main radiator. You shouldn't really be seeing intake temps that high with only 7psi of boost...

Lag the exhaust manifold up to the turbo but only shield the turbo. As others have said, you want to keep the exhaust velocity up for good performance of the turbo.

Make sure your system is bled properly but always use a thermostat.

Cheers,
Rich
All these mods are detailed on my site...

Great to see you on the forum.
Have been to ur site a few times. I think I have controlled the hi temp issues in the cooling system with fan flow, bleed points etc, so I don't think there is such a problem. I did consider an upfront radiator but being a full belly pan the running of coolant lines would be rather interesting. I wouldn't want lines up thru the cockpit, as even when insulated they will still radiate heat and would look kinda out of place. The object is to have a standard looking 550 from the outside so any ducting if required would be hidden within engine compartment. If I stay with the EA82T then I will be fitting an intercooler, but I am leaning now to a EJ20T/gearbox as a package as in ur install. Have a supplier here in Sydney with factory new EJ20T engines with only factory run miles for $3950 A.
Whats happening with the Ghia???

[Edited on 5-2-2003 by speedster356]

Hi,
The main reason I said about the front mounted rad is that a UK company (Martin & Walker, also known as Technic) also supply Alfa powered cars and they fit the rads up front, the standard grill seems to allow enough air flow. I think this would be the way to go for you, especially if you want an EJ20T! You could do some quick calcs to compare the flow of an aftermarket fan and then compare this with the air flow through an intake area at a given speed, you'd be surprised at the difference! I'm sure there must be some way of hiding the pipework, once lagged they wouldn't radiate any noticeable heat. I don't notice any heat coming from my pipework in my false floor, I wish I did as this morning it was below zero!
A friend is also considering putting the EJ20T in his Spyder and looked into using the Scooby transmission. It is possible to weld up the output and to drive it through the 'front' wheels, but they are a weak link in the Subaru with only half the torque going to each axle... Food for thought anyway, I know it's be nice to have the factory 5 speed and no adapter hassles...

The Ghia is on hold at the moment while I develop my 'bolt on' front double wishbone kit for VWs. The plan is to fit the first to the speedster for testing and then get it productionisedhttp://www.ricola.co.uk/wishbone.htm Only problem is that my wife wants me to sell the Ghia and buy her a sensible car now😠

Rich

Yeah the gearbox is a small problem. I'll most likely use the 2.5ltr gearbox and use a splinned adapter between the shafts. This has been used with great success in NZ applications. The available torque is the killer, so I promise I'll be gentle.........
I think I will remain with the rear radiator, with ducting.
I have about a 600mm wide x 40mm deep ducting frontal area available between the engine and the firewall for air pickup (this is were the belly pan ends), this should be ample for higher speed cooling.
WHAT...she who must be obeyed wants a WHAT????
cheers

Lol! I gave her my old Fiat which forced the speedster into daily use no matter the weather. She has a baby and all of a sudden she wants something better to compete with all the other 4x4s that the other mums have... Hopefully once she sees the Ghia finished sh'll change her mind...
What applications have you seen the 2.5 gearbox used in (NZ)?
Rich

2.5 gearbox in Spyders.
There is a company in Europe that a Sydney supplier ships engine/gearbox packages 2. Can't remember the kit car name......

Hi Peter

A good article to read at Autospeed about air/water ics http://www.autospeed.com/A_0090/cms/article.html

Some motors use a 2 stage thermostat, you cant remove these because as the thermostat opens a 2nd part of the thermostat closes of another passage.

To aid in bleeding I drilled a tiny hole in my thermostat, I can fill my motor at the header tank OK without having to bleed it, the expansion tank takes care of any left over air bubbles as I drive.

Most VW & Audi radiators use rubber flaps that push away allowing airflow through the radiator at highway speeds but get sucked shut when the fan comes on, this allows the fan to suck only air from the other side of the radiator.

1302Steve

Yeah I did see on a Subaru/Spyder install in the states 3 "D" shaped rubber flaps on the fan shroud. I did wonder what they were.